Saw-tooth wave generator



April 18, 1950 R. LEE 2,504,849-

SAW-TOOTH WAVE GENERATOR Origihal Filed Sept. 12, 1946 lun VVYVVVV E l I 32 Fig.5. I

WITNESSES: INVENTOR Reuben Lee.

BY 1 W i atenteti Apr. i8,

2504,8419 snw 'roozrn WAVE GENERZSETOfi iiuben rleeiistmttm Heights; WeSti'l'igHflQSQElCtliC Corporatio =0riginal application septenihemlfi, .1946, .Se'rial "relates to oscill'ation generators 1 ar,"t o a new typefofoscillation cnlarlyadaptedto the production ap [n "a division of iny Patent j filgfiledsebtember 12, 19%,6, for a Sawth "w .igenerator, and assigned to the f the application. H

, (st of my invention is to -prodncega t or sharply peaked Waves 1 which "shall a x n ramp i e-m r beot'fof"my'invention"is to provide a aves--of'-the sg'eneral sawtooth for-m Whi'chfshafl involve only-relatively 1 simple *cirouit 9 l 5 fptiion o is an N 696, 4,. Divided d-this application: uly eais is serial No. 40,119

i' eiaims. (arterio es) curve'e ,"'afidsunplid'froin a sine wave alter fiat 1vvl'i'ieh lags slightly in phase relative to that fsiip ipl'yihg' therlctifierof Output "e1. Whhthe' ordinates of'the curves erandez of l aie added together, 'a curve oftheWa'V'e form e'zjshown inFig. 2 results. It wnr-be noted that in Fig."2 the downward slope j of the curve is ot 'e'iiac'tlyj rectilinear,bntfthat'the eurve ix es airapproiiinationito'a'sawtooth wave. Vary the? "displacement between'th'e curves e1 'and z "W111 ehange"th e amount of the' departyre 'o'ikthe "ddwnslope from rectilinearity-"and also-efiane'th'e amplitude of the peaksand t sojjf' the wavefandthe ratio of op -slope to,oown-1s1ope. 'I-IoweWrr, the CllrVe'eyi1l"Fig.2 probably "represents about the best approximation to arectilinear down slopeihat' can be obtained, fxiiith the phase displacement between iiand e 2f such"as"t0give steep rip-slope; I lI'Cuit networkcana'ble of producing voltage offi'the wave form as is'shown in Fig; 3 wherean ordinary high vacuum 'tri'ode' I has its plate fcirci1'it1 provicie'd'fwith an; antiresonanttuned netcomprising; an' inductance '2 and aycapaci- Z- E ieiht iit a cir id as circuit -:ejc 'inp 1fi'singa resistance 'Iniajnanner well'known l it, srid"s 'c t ndth pate mv gifthe tube? l areinagnetic'ally interlinked; for "eiganipl'efbyi -locating the inductance z ne-a inductance Finthe grid circuit inmu tnally in'ductive relation-toeaclr other. *The cirqnitfl'to 6 iITbe'r'ecOgniZed as an ordinary jb'adk oscillator and such oscillators ean be inane by "well" known methods of adjustment to p'rodfice' output voltages which approximate very closely" tof the sine wave form. This particular typepf' oscillator is to*be taken-merely-as--syhib" ieal ofa'ny's uitablesine'wave generator known i ri- 11in output coil 1,-' 1na1;t;1ve1 linked with-the load circuit' of the oscillator l, is connected' 'to two transformer primaries-'8; 9. A 'seeondary l l associated With the primary 'windin a has its end terminals eonn'ected thronghapair-of rectifiers l2; I 3 which may, "for exam-1e; be hiQgh'fV-aC- 1mm diodes,-or, alternatiyelyjb op xid tifiers'or any other suitabletype of rectifier. The primary winding 9 is associated with a seondar y xifindiiig I4 across the terminals of which are seriallyeonnectedaVariable resistor l 5 anda caso or l6. Thecornn' -onterminal of the resistor l5 -and the capacitor is connected to o'nefterinitialofa primarywmding H, the other terminal ofivhih is corinected to t'he midpoint Of the winding M. A secondary winding l8, associated with the primary winding IT, has its end terminals connected to a pair of rectifiers I9, 2| which may be of the same general type as the rectifiers |2, |3 already mentioned. The midpoint of the secondary winding I l is connected to the midpoint of the secondary winding l8, and the common terminals of the rectifiers l2, l3 are connected to one side 22 of an output circuit in which it is desired to use a wave form of the type shown in Fig. 2, the other terminal of this output circuit being connected to a line 23 connected to the common terminal of the rectifiers l9, 2|.

It will be recognized that the resistor l and the capacitor IB constitute a phase-displacing circuit by which the alternating voltage impressed on the primary winding may be displaced to any desired degree relative to the alternating voltage impressed on the primary winding 8. By properly designing, in ways which will be evident to those skilled in the art, the size of the transformer windings above mentioned or, alternatively, by properly adjusting the resistor l5 and capacitor It, the relative amplitudes and phase of the rectified voltage waves produced respectively by the rectifiers I2, 13 and |9, 2| may be adjusted at will. A moments consideration of the above-described circuit will show that the rectifiers l2, l3 will produce an output voltage similar to e1 in Fig. 1, While the rectifiers l9, 2| will produce a rectified voltage of opposite polarity displaced in phase relative to the output of rectifiers i2, i3, and hence a voltage similar to e: in Fig. 1 across the terminals of the rectifiers l9, 2|. A voltage will be produced across the line wires 22, 23, which will have the wave form shown in the curve es in Fig. 2.

In Fig. 4, I show an alternative form of network which may be connected to the output of rectifiers l2, l3 and i9, 2| in Fig. 3 to produce a wave form of the type shown in Fig. 2. When the arrangement shown in Fig. 4 is to be used, the line wire connecting the midpoints of secondary windings H and i8 is broken. A moment's consideration will show that between the midpoint of the secondary winding I and the common terminal 22 of rectifiers l2, I3 is, produceda voltage of the form e1 in Fig. 1, while a voltage of the wave form eg in Fig. 1 isv produced between the output terminal 23 and the midpoint of the winding 18 in Fig. 3. The terminal 22 and the line leading to the midpoint of winding H in Fig. 3 are then connected between the terminals 24, in the network shown in Fig. 4, while the terminal 23 and the midpoint of the secondary winding 93 in Fig. 3 are connected, respectively, to the terminals 23 and 2? in Fig. 4. Between the terminals 24 and 2? in Fig. 4 are serially connected a pair of impedances 28, 29 which may be resistors, While a third impedance 3|, which may likewise be a resistor, is connected between the midpoints of the impedances 28, 29 and the line interconnecting terminals 25 and 26 in Fig. 4. A moments consideration will show that the voltage across the terminals of the impedance 3| will be the algebraic difference of the voltages c1 and e: of Fig. l; in other words, the voltage across the impedance 3| will have the wave form ea shown in Fig. 2.

If a voltage of the wave form e1 of Fig. 1 is connected across a capacitance 32 in series with a resistance 33, as shown in Fig. 5, the Wave form across the resistance 33 will be of the type shown in Fig. 6. It will be noted that the downward slope of the waves shown in Fig. 6 is not recti- 4 linear but is curved in a sense opposite to the curvature of the down slope of voltage ea in Fig. 2. The degree of departure of the down slopes in Fig. 6 from rectilinearity is a function of the relative magnitudes of the capacitor 32 and the resistor 33 in Fig. 5.

Since the curvature of the down slope in Fig. 6 is the reverse of the curvature in the down slope of the voltage as in Fig. 2, it will be evident that by properly proportioning the size of the capacitor 32 and the resistor 33 in Fig. 5, it will be possible to cause the curvature in the down slope of the curve or of Fig. 6 to exactly compensate for the reverse curvature in the down slope of the curve es in Fig. 2 if the voltages e; and e; are added together in a circuit. When this is done, a curve of the form as shown in Fig. 7 in which both the up-slope and down-slope of the Wave are almost exactly rectilinear will be obtained.

Fig. 8 shows a network in which the voltage of the wave form e: and et are properly added together to obtain a wave form of the type shown in Fig. '7. In this case one branch includes a parallel network comprising an inductance 38 and a condenser 39 connected in series with resistor 4 a second branch consists of the resistor 42 and the third branch of the resistor 43. The voltage e1 is impressed across the terminals 34-35 and the voltage as across the terminals 35-3'|. The sawtooth voltage e5 having a wave form of linear negative slope is derived across the resistor 42.

With the rectified voltages c1 and as derived from a 60cycle supply, a voltage or of wave form, the negative slope branch of which is linear, was derived with components as follows in th branches of the circuit shown in Fig. 8.

Inductance 38 between 5 and 10 henries Capacity 39 between .33 and .66 mfds. Resistance 41 10,000 ohms Resistance 42 200 ohms Resistance 43 10,000 ohms While, in accordance with the patent statutes, I have illustrated particular embodiments of my invention, it will be recognized by those skilled in the art that the principles thereof are of broad application in ways which will be evident to them.

I claim as my invention:

1. In combination with a source of sine wave voltage, a first full-wave rectifier supplied from said source, a second full-wave rectifier supplied with sine wave current of the same frequency as said source, but phase displaced relative thereto, a network having four terminals, an inductor shunted by a capacitor connected in series with a resistor between a first and a second of said terminals, a resistor connecting an intermediate point on said resistor with both the third and fourth of said terminals, means for connecting the output of the first-mentioned rectifier to the first and third of said terminals, and means for v connecting the output of said second rectifier to the second and fourth of said terminals.

2. In combination with a feed-back oscillator,

a first rectifier supplied with the output voltage point on said resistor with the second and fourth of said terminals, and means for connecting the output terminals of said first rectifier across said first and second terminals and for connecting the output terminals of said second rectifier across the third and fourth terminals.

3. In combination with a source of sine wave voltage, a first full-wave rectifier supplied from said source, a second full-wave rectifier supplied with sine wave current of the same frequency as said source, but phase displaced relative thereto, a network having four terminals, an inductor shunted by a capacitor connected in series with a resistor between a first and a second of said terminals, a resistor connecting an intermediate point on said resistor with both the third and fourth of said terminals, means for connecting the output of the first-mentioned rectifier to the first and third of said terminals, and means for connecting the output of said second rectifier to the second and fourth or said terminals.

4. In combination with a feed-back oscillator, a first rectifier supplied with the output voltage of said oscillator, a second rectifier fed through a phase-displacing network with the output voltage of said oscillator, a network comprising four terminals, the first and third of said terminals being connected by a channel comprising an inductor shunted by a capacitor in series with a resistor, a resistor connecting an intermediate point on said resistor with the second and fourth of said terminals, and means for connecting the output terminals of said first rectifier across said first and second terminals and for connecting the output terminals of said second rectifier across the third and fourth terminals.

REUBEN LEE.

No references cited. 

